Statistical multistep reactions from 1 to 100 MeV

Kalka, Harald

doi:10.1007/bf01283537

Cited by 16 publications

(5 citation statements)

References 24 publications

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“…A possible explanation of the data can be that at forward angles the relative contribution of direct process is about 50% or more. However, different direct reaction calculations [7][8][9] are in remarkable agreement and give about 7-10% relative direct reaction contribution at E n =3-3.5 MeV and 1-2% at E n = 1-1.5 MeV in the angle integrated spectrum. As a result, analysis [8] of the above reaction at E n =3 MeV in the framework of a modified FKK approach gives σ(30 • -70 • )/σ(120 • -140 • ) ≤ 1.1 while the experimental value is about 2.…”

Section: Introductionmentioning

confidence: 91%

“…The aim of this work is to present an interpretation of the forward peaking in the evaporation domain of the spectrum (where the contributions of both direct multistep and compound multistep pre-equilibrium processes are negligible [7][8][9]) in terms of the Feshbach S-matrix pole expansion. We present a possible justification of correlations between fluctuating S-matrix elements carrying different orbital momenta, total spins and parities.…”

Section: Introductionmentioning

confidence: 99%

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Statistical reactions with memory and thermalized-nonequilibrated nuclear states

Kun

1997

Z Phys A - Particles and Fields

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Starting from the Feshbach S-matrix pole expansion we modify the standard statistical model for compound reactions by introducing correlations between fluctuating Smatrix elements with different J (total spin) and π (parity) values. The S-matrix (J, π)-correlations are obtained at the expense of introducing infinitesimally small entrance-exit channel off-diagonal (J, π)-correlations between the random variables of the statistical model. Although later on these correlations are switched off by means of a properly applied limiting procedure, the S-matrix (J, π)-correlations do not vanish and can be strong. The physical origin of the S-matrix (J, π)-correlations resembles the effect of spontaneous symmetry breaking while S-matrix (J, π)-decoherence is due to quantum chaos. Novel reaction mechanism results in the excitation of peculiar nuclear states: The intermediate system is thermalized so that the shape of the spectrum is angle-independent and Maxwellian with angle-independent slope, yet the intermediate nucleus is not equilibrated since the angular distribution is forward-peaked, i.e., memory of the direction of the initial beam is not lost. The existence of thermalized-nonequilibrated nuclear states is supported by data on the 50-100% forward peaking of neutrons in the typically evaporation (1-3.5 MeV) part of the spectrum observed in the 93 Nb(n, n ) scattering with E n = 7 MeV.

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Section: Introductionmentioning

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Statistical reactions with memory and thermalized-nonequilibrated nuclear states

Kun

1997

Z Phys A - Particles and Fields

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“…1. A modified version of the code EXIFON [10] is used as an alternative code for N and O as well. For energies below 150-250 MeV, the conventional codes used widely in the evaluations below 20 MeV are applied, and Monte Carlo calculation codes based on the intra-nuclear cascade (INC) model or quantum molecular dynamics (QMD) are used mainly for those above 150-250 MeV.…”

Section: Nuclear Model Calculation Code Systemmentioning

confidence: 99%

Nuclear Data Evaluations for JENDL High-Energy File

Watanabe

Fukahori

Kosako

et al. 2005

AIP Conference Proceedings

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An overview is presented of recent nuclear data evaluations performed for the JENDL high-energy (JENDL-HE) file, in which neutron and proton cross sections for energies up to 3 GeV are included for the whole 132 nuclides. The current version of the JENDL-HE file consists of neutron total cross sections, nucleon elastic scattering cross sections and angular distributions, nonelastic cross sections, production cross sections and double-differential cross sections of secondary light particles (n, p, d, t, 3 He, α, and π) and gamma-rays, isotope production cross sections, and fission cross sections in the ENDF6 format. The present evaluations are performed on the basis of experimental data and theoretical model calculations. For the cross section calculations, we have constructed a hybrid calculation code system with some available nuclear model codes and systematics-based codes, such as ECIS96, OPTMAN, GNASH, JQMD, JAM, TOTELA, FISCAL, and so on. The evaluated cross sections are compared with available experimental data and the other evaluations. Future plans of our JENDL-HE project are discussed along with prospective needs for high-energy cross section data.

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“…The second term represents the statistical multistep compound (SMC) emission. Both terms together (SMD+SMC) represents the first-chance emission process (Kalka, 1992). The last term of equation (21) represents the multiple particle emission (MPE) reaction which includes the second-chance, third-chance emissions of particles, etc.…”

Section: Statistical Multistep Reactionmentioning

confidence: 99%

Calculation of reactions cross section for proton-induced nuclear reactions on Iodine-127 isotope

Ahmad¹,

Koki²,

Yola³

2019

Bayero J. Pure App. Sci.

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INTRODUCTION At present day, radioisotope production for nuclear medicine is important because of its common use in tomography devices. Both single photon emissions computed tomography (SPECT) and positron emission (PET) is used for diagnosis in nuclear medicine(Ahmad and Koki, 2017) particular, the radionuclide of iodine is used for these purposes. Therefore, these radionuclides play an important role in medical applications and research. For example, Gamma-emitted short long live 124 I(Artun and Aytekin, 2015) can be used as the diagnostic image in SPECT and PET. Besides, 124 I allows for studying important organs such as the brain and heart (Alharbi & Azzam, 2012). The long isotope also is used as a source for internal radiotherapy, bone dosimetry and a biological tracer (Skakun & Qaim, 2008). Another iodine radionuclide 122 I is a very short and used in PET for brain blood studies(Qaim, 2004, Qaim, 2017 During the last two decades, several semi classical and quantum-mechanical models have been developed to treat equilibrium phase of reactions leading to the formation of the compound nucleus. The very first model is capable of reproducing the shapes of the continuous spectra 1966). He reported that "if one is overlook the justification and retain the assumption of a binary collision even at lower energies, one can qualitatively explain some ABSTRACT Radioisotope production for nuclear medicine is tomography devices. Both single photon emissions computed tomography (SPECT) and positron emission tomography (PET) is used for diagnosis in nuclear medicine we have calculated the reaction cross secti the formation of , , , particle with the nucleus of the iodine variation of interaction crossresult shows that the plots of curve. The productions confirm the presence of Xenon possible at the energy range of 0 to 30 MeV from the iodine

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Statistical multistep reactions from 1 to 100 MeV

Cited by 16 publications

References 24 publications

Statistical reactions with memory and thermalized-nonequilibrated nuclear states

Statistical reactions with memory and thermalized-nonequilibrated nuclear states

Nuclear Data Evaluations for JENDL High-Energy File

Calculation of reactions cross section for proton-induced nuclear reactions on Iodine-127 isotope

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